Try San Gregorio Beach. I used to drive down from SF to go there. Quiet and mostly gay. You can wear anything or nothing at all.
Below is a Yelp review of the beach. Read through the comments for accurate directions and information. The entrance to the gay/nude part is north of the real beach.
https://www.yelp.com/biz/san-gregorio-beach-south-coastside?osq=gay+nude+beach